Closure operator



March 4, 1930. M. R. HARRIS 1,749,425

CLOSURE OPERATOR Filed Feb. 15, 1926 INVENTOR.

,4 ATTORNE Patented Mar. 4, 1930 PATENT OFFICE MARCUS R HARRIS, or DETROIT, MICHIGAN CLOSURE OPERATOR Application filed February 15, ,1926. Serial No. 88,277.

The present invention relates to closure operators and specifically to garage doors and Igeans for compensating for the weight there- Heretofore, in doors of this type the ordinary method of counterweighting has been to so apply the weight that it exerts a substantially constant effect. With doors arranged to travel upward and then horizontally so that, when fully opened, the door is supported upon a horizontal track, this form of counterweight is objectionable in that during the latter portion of its travel in opening the weight of the door is very much overbalanced by'the counterweight.

In the usual use of springs, the same objection exists.

Among the objects of the present invention, therefore, is to overcome this objection and provide means whereby the effect of the counterweighting' varies with the position of the door and is substantially nil when the door-is in its horizontal, fully-open position.

With this and other objects in view as will more clearly hereinafter appear, the invention consists in the novel combination of elements illustrated, in the accompanying drawing and in such modifications and variations therein as will be obvious or within the skill of those skilled in the art and come within the scope of the claimwhich is hereunto appended.

In the accompanying drawing illustrating a preferred embodiment of the invention,-

Fig. 1 shows a side elevation of a door and counterweight with parts in section; and

Fig. 2'is a horizontal section on they line 22 of Fig. 1.-

In the drawings the numeral 10 indicates a garage or other building provided with the usual door frame 11. The door 12 is adapted, in closed position, to press tightly against the inner edge of the frame 11 and is opened by liftin it bodily upward and away from the framIa.

In order to permit this movement of the door, it is made in several sections 12*, 12 and 12", as indicated, and each section provided with rearwardly extending arms 13 cariying rollers or trolley wheels 14; cooperatopen position, so that the door lies in substantially a horizontal position almost entirely supported by the horizontal portion of the track.

As doors of this type are usuallyof considerable weight, they must be counterpoised, and in the present invention the door is counterweighted by means in which the effect is gradually lessened as more and more of the door is supported by the horizontal track.

The counterweight means is shown as a weight 20 fixed upon and adjustable lengthwise of one spoke of a sector 21 of a pulley pivoted at 22 upon a suitable support, means such as the set screw 2O being provided to secure the weight in adjusted position. The sector is provided with a groove 28 on its curved edge in which is received a rope or cable 24 secured to the sector opposite the.

weight 20. This cable 24 extends, in the form shown, vertically to a pulley 25 and then horizontally to another pulley 26 and then forward to the center of an equalizer bar 27. At each end of bar 27 other cables 28 extend over pulleys 29 down along the lateral edges of the door to the bottom thereof and are secured to the lower end of the bottom door section.

The cables 24 and 28 are of such length and the radius of the sector such that, when the door is shut, the weighted spoke of the latter is substantially horizontal and the weight 20 accordingly exerting its greatest pull, while,

when the door is completely open, the weighted spoke is hanging substantially vertical with the cable 24 lying in groove 23.

The adjustability of weight 20 provides means whereby a given sector and weight may be used with diiferent weights of doors.

This arrangement of the counterweight provides the operator of the door with the most assistance when the most 01 all of the weight of the door must be moved and also offers the least resistance when the weight of the door is almost if not entirel supported by the track, that is, when the oor is to be moved from wide-open position.

It is preferred to arrange the parts as indicated, with a single sector and an equalizer, but it is obvious that two such sectors might be used, one connected to each side of the door. It is also obvious that other suitable locations than on the side of-the building may be used for the sector.

Further,while the sector shown and described represents a sector of a circular pulley, it is obvious that other shapes may used, e. g. a portion of an oval or the curved side may be spiral. In these other instances the basic idea is the same and therefore the claim is intended to include such structures within its scope.

Having now described the invention and the preferred form of embodiment thereof, it is to be understood that the said invention is not to be limitedto the specific details herein described and illustrated but only by the scope of the claim which follows.

. I claim:

Counterweight means for doors adapted to be lifted from closed position and guided to horizontal open position'wherein said doors are supported by the guiding means, said counterweight means consistin of a sector of a grooved pulley having spo (es, a weight secured to one of said spokes, and a cable connection from the outer end of said weighted spoke to said door, said cable being of such length that said weighted spoke assumes a horizontal position with the rest of the sec-. tor above, when said door is in-closed po-' sition.

MARCUS R. HARRIS. 

